Amarin Corp. lost more than half its value in early trading after the company failed to win the backing of U.S. advisers to expand use of its fish-oil pill Vascepa for those with high levels of fat in their blood. Amarin’s American depositary receipts fell 62 percent to $1.97 at 7:52 a.m. New York time. The company had already dropped 54 percent in the 12 months through Oct. 15. Trading was halted yesterday during the advisory panel meeting.